1. Field
The present embodiments relate to a capacitive pressure sensor and a method of manufacturing the same. The present embodiments are operative with various sensors and gauges. For example, the present embodiments are operative with a barometer for monitoring an atmospheric pressure or a capacitive pressure sensor for monitoring a gas pressure.
2. Related Art
Generally, a capacitive pressure sensor is configured such that a substrate having a diaphragm corresponding to a movable electrode is bonded to a substrate having a fixed electrode with a predetermined gap (cavity) between the diaphragm and the fixed electrode. For example, a capacitive pressure sensor is disclosed in Japanese Patent No. 2772111. In this capacitive pressure sensor according to the related art, if pressure is applied to a diaphragm, the diaphragm deforms, which results in varying an interval between the diaphragm and a fixed electrode. As the interval between the diaphragm and the fixed electrode varies, an electrostatic capacitance between the diaphragm and the fixed electrode varies. The variation in the pressure is detected by using the variation in the electrostatic capacitance.
This capacitive pressure sensor has been required to have a small size and a small cavity gap between the fixed electrode and the movable electrode. In the capacitive pressure sensor, it has been required that high pressure be detected even when the cavity gap is small. Accordingly, the capacitive pressure sensor has been required to detect pressure with high sensitivity.